Some time ago, a newspaper article said that the residents of Uncertain, Texas, were no longer uncertain as to whether or not they lived in Uncertain. This uncertainty was resolved because Judge C. L. Ray had officially decreed that the election resulting in the incorporation of the city of Uncertain, Texas, was valid. By a vote of 58 to 11, the city of Uncertain was created. There is no longer any uncertainty concerning the certainty of the fact that some people live in Uncertain. However, when traveling abroad and filling out forms that specify “place of residence,” the residents of this town must write down: Uncertain.

Although by God’s grace we are not spiritual residents of the city of Uncertain, we must confess that too often we are also strangers to that city called Full Assurance of Faith (Heb. 10:22). What does Scripture teach about the certainty of our hope of salvation? How can we grow in our own assurance of God’s grace?

God not only rescues His people from their sins; He also grants them assurance of salvation. In several ways, we see God at work assuring His adopted children that they are truly part of His family. The Father gives His children the promise of adoption in His Word; He sends the Spirit of His Son into our hearts to assure us, and He changes our lives so that we bear an imperfect, but real, family resemblance to Him and His Son.

The Promise of Adoption

At times Christians get confused in their pursuit of assurance of salvation. Some seek assurance chiefly in spiritual experiences. Some constantly scrutinize their hearts in hope of gaining certainty of eternal life. Others put the emphasis on their walk with God. None of these, however, is the first and most important reason for the assurance of salvation.

That pride of place belongs only to the Word of God. The Father tells us in His Word that He has adopted us. As a result of the Father sending the Son and the Spirit, Paul assures each believer in Galatia, “So you are no longer a slave, but a son; and since you are a son, God has made you also an heir” (Gal. 4:7). Although we once were slaves of sin and Satan, we are no more. God declares it in His Word and it is so: We are God’s sons and daughters.

God the Father’s promise of adoption is expressed in two main ways in Scripture. Sometimes the emphasis falls on human responsibility: adoption is by means of faith. “You are all sons of God through faith in Christ Jesus” (Galations 3:26). Here, God states a fact: all who believe savingly in His Son are sons of God. The same truth is repeated in John 1:12: “Yet to all who received Him, to those who believed in His name, He gave the right to become children of God.

At other times in God’s Word the assurance of adoption is expressed in terms of His sovereignty: adoption is grounded in God’s prior choice of His people. “In love He predestined us to be adopted as His sons through Jesus Christ in accordance with His pleasure and will” (Eph. 1:5). God chose us unto adoption. His choice of us is the ultimate reason why we are God’s children.

Sometimes, however, people nervously ask, “How can we know that we are predestined unto salvation?” Paul answers this question in 1 Thessalonians 1:4-5: “For we know, brothers loved by God, that He has chosen you, because our gospel came to you not simply with words, but also with power, with the Holy Spirit and with deep conviction.”

How do we know that people are chosen by God for salvation? Only by the fact that they trust Christ. Scripture never instructs us to try to figure out the eternal counsels of the Almighty. Indeed, that would be a hopeless pursuit. Instead, it points us to the gospel.

Ultimately our adoption rests on God’s love, pleasure, and will. It is a great comfort for God’s children to rest in their Father’s all-powerful arms. No matter what our age, we are all little ones climbing up into the armchair and snuggling with our Father. We love and trust Him; but His love and will support our faith, not the other way around.

Not only does the Spirit enable us to believe the message of adoption, He also bears witness within our hearts that the message is true.

Whether God’s plan or human freedom is mentioned, the result is the same: in Scripture God declares that we are in truth His sons and daughters. The bedrock of our assurance of adoption is God’s Word. God has told us plainly and repeatedly that He has given us the privilege of sonship.

The Spirit of Sonship

The promise of God the Father is the primary way that He assures us of sonship, but it is not the only way. Along with the promise of salvation, God gives us His Holy Spirit. The Spirit of sonship assures us within of God’s love for us. The most important passage of Scripture on this topic is Romans 8:15-16, “For you did not receive a spirit that makes you a slave again to fear, but you received the Spirit of sonship. And by Him we cry, ‘Abba, Father.’ The Spirit Himself testifies with our spirit that we are God’s children.”

Not only does the Spirit enable us to believe the message of adoption, He also bears witness within our hearts that the message is true. The Spirit whispers in our spiritual ears that we are God’s sons and daughters.

Chiefly, God assures us of salvation by telling us in His Word that we are adopted. But He does not stop there. He also grants us an internal witness of our adoption. This is wonderful and is an evidence of God’s deep love for us.

Is it possible to say more about the Spirit’s witness with our spirits? My answer is a cautious “yes.” The Holy Spirit assures us of adoption personally, supernaturally, individually, and inscrutably. Each of these adverbs deserves our attention.

The Spirit of sonship assures us personally. 
The Spirit’s witness is given only to those who believe the gospel. But it is distinct from our faith in God’s Word. This is an additional witness. God bears witness to our sonship both in Scripture and also by His Spirit in our inner being. The Spirit assures all Christians deep within their hearts that God loves them. He intimately fits His witness to their individual personalities, life stories, circumstances, etc., that God is their Father and that they are His children.

The Spirit of adoption assures us supernaturally.
This is not an assurance that one human being can give to another. It is given by God the Holy Spirit Himself. It cannot be achieved by human accomplishment, as if praying or reading the Bible for a certain length of time automatically conveyed it. Instead, it is a divine accomplishment, as much as creating the world or raising the dead. We are utterly dependent upon Almighty God to assure His people within. And the fantastic thing is that He does just that. All who believe in Christ receive the supernatural internal witness of sonship, a witness that transcends our understanding.

The Spirit of sonship assures us individually.
This inner testimony of God’s spirit is given not only to spiritual giants, but to pygmies like you and me. It is not only experienced at times of great spiritual success, but commonly is felt most keenly at times of spiritual defeat. Just when we groan under our sins, perhaps nearing what seems to us to be our breaking point, then–of all times–we sense the still small voice of the Spirit within say, “I love you. You are mine and I love you.” At such times we feel so unworthy of the Father’s love. The truth is we are always unworthy of His love; that’s what grace is all about. But it sometimes takes our failures for us to realize our desperate need.

The Spirit of adoption assures us inscrutably.
It is not good for us to pretend to understand more than we do of God’s works and ways. Such spiritual pride ill befits the sons and daughters of the living God. We are especially ignorant of the works and ways of God the Holy Spirit. Who can explain how the Spirit regenerates sinners who are spiritually dead (John 3:8)? Who can understand how the Spirit of God sets apart defiled sinners, spiritual lepers, from sin unto holiness, so as to constitute them saints of God (2 Thessalonians 2:13)? Who can fathom how the Spirit joins lost men and women to the Son of God, so that henceforth they are united to Christ (1 Cor. 12:13)? Nevertheless, based upon the authority of God’s Word, we can say with confidence that the Spirit does regenerate and sanctify sinners and join them to Christ. But as to how the Spirit accomplishes these mighty works we cannot say. We see the results of His work, but we cannot predict, control, or even fully comprehend it.

Those adopted by the Father share in the sufferings of His Son. That is a great responsibility. But this too is set within a framework of blessing, this time future blessing.

The same is true with reference to adoption. We see the effects of the Spirit’s work when a slave to sin cries out, “Abba, Father,” the first cry of saving faith. But we cannot trace how the Spirit has worked to bring that human being to that place.

Phil, a former campus minister, shared with me the Father’s gracious dealings with him by the Spirit of adoption. He wrote, “I came to a point of deep pain in 1990, where the outside world saw my spiritual leadership as a campus minister and thought everything was fine, yet there was a lack of authentic presence and power within my personal life. I would look in the mirror at a hypocrite every morning. My wife was very helpful at this time, but my supreme help came from the Lord, as I was asking hard questions about myself, faith, theology, etc. On September 19, 1990, a red-letter day I’ll not forget, I was roaming through the book of Romans, desperate, and came across Romans 8:16. I cannot articulate well what came next, except to say that I experienced that verse. God’s Spirit testified that I was His son. And even more remarkably, my spirit joined in and testified that I was God’s son. That exchange was so deep that it stands out as my most memorable experience. I don’t talk about it much, but it rocked my world and set me on a course of positive change in theology, direction, marriage relation, and calling. Perhaps the biggest change was a better alignment between my public life and private life. To God be the glory.”

We too glorify God for His working in Phil’s life. It is important to add, however, that not everyone shares Phil’s experience. In my case the Spirit’s witness in the first year after my conversion to Christ at 21 was not dramatic; instead, it was more like a still small voice. The main point is not that the Spirit’s witness always conforms to one pattern. It does not. Rather, the main point is that the Spirit’s witness is real, whether dramatic or quiet.

A Family Resemblance

Our dear Father assures us of adoption primarily by making promises of sonship to us. He promises in His Word that all who believe in Christ are sons or daughters of God. He goes beyond that and also sends the Spirit of sonship on a special mission. The Spirit assures us within that we are God’s. The Father assures us in a third way as well: by virtue of the principle of family resemblance. I read a story about a woman who was talking to her daughter and commented how her eyes looked just like her father’s. The daughter said, “But Mom, I’m adopted!” The mother replied, “Oh, yes, I always forget.”

Like devoted human parents, God loves His children. Unlike human parents, He has the power to cause His adopted children to bear a family resemblance. Our Father frees us from bondage and gives us the status of sons (Gal. 4:5,7). One of the results is that our character begins to resemble His. The resemblance is far from perfect, but it is real. The Father begins to conform our lives to His and thereby encourages us that we are really members of His family.

God’s children are identifiable. This is the teaching of Romans 8:14, “Those who are led by the Spirit of God are sons of God.” The leading spoken of here is akin to the way an army sergeant leads a platoon of privates. The sergeant directs and commands the privates; He authoritatively leads them in the way He wants them to go. The Spirit of sonship does the same. He authoritatively leads the sons and daughters of God in paths of righteousness and kindness. He directs and commands them to do the Father’s will. And because He does so, they are recognizable.

The children of God walk in His ways and follow His commandments. This is not how they get into God’s family–that is by grace alone through faith in Christ alone–but once in the family, God’s children bear a family resemblance to their Heavenly Father.

Sharing His Suffering

Discussing family resemblance suggests a topic frequently mentioned in the Bible, but not well known among many modern evangelicals–suffering. Often Scripture puts privilege and responsibility side by side. For example, Paul speaks of great spiritual privilege when he writes, “Now if we are children, then we are heirs–heirs of God and co-heirs with Christ … .” The apostle adds a qualifier: “… if indeed we share in his sufferings in order that we may also share in his glory” (Rom. 8:17).

Those adopted by the Father are His children and heirs. That is a great blessing. Those adopted by the Father share in the sufferings of His Son. That is a great responsibility. But this too is set within a framework of blessing–this time future blessing. God’s children will share in Christ’s glory in the future. More than we might realize, suffering for Christ is a mark of sonship.

God the Father assures us of our sonship in three ways. He promises to make us His sons in His Word, He sends the Spirit of His Son into our hearts to assure us, and He changes our lives so that we bear an imperfect–but real–family resemblance to Him and His Son. We should view the witness of Word, Spirit, and changed life as manifestations of God’s grace working together to give a strong measure of assurance.

Let us rejoice in our status as God’s daughters and sons and not forget our identity in Christ. And let us enjoy a full measure of assurance by believing His promises of sonship, by listening to His Spirit, and, by His grace, bearing a family resemblance to our dear Father and His beloved Son.


Dr. Robert Peterson serves in the theology, tradition, and mission department at Covenant Theological Seminary. Peterson is the series editor for the “Explorations in Biblical Theology” series, published by P&R Publishing. He is currently writing Preservation and Apostasy, which is part of the series.


Reprinted with permission from Covenant, the magazine of Covenant Theological Seminary. To access many more free resources in a variety of media formats, visit online at